180 main jet (help!)

MichaelAngelo

Any body run a 180 main jet? I have been using a 175, with a 48 pilot jet. Bike ran good. However, my friend who has a 426 (i own a 400) has had the benifit of all my TT inspired free mods because I graciously shared the info with him. He's not very mechanical so I did the work as well. I did shave his throttle stop a bit longer than mine. In any case I want to out perform him. We are pretty evenly matched in terms of riding ability and I'm just looking for an edge. Will the 180 main jet hurt the bike ?(bend a valve or something)I'm going to run a 14/53 gearing like Yamakazi, but I don't know if it will be that noticeable. I want to suck 'em up on the track. Thanks,

MOmilkman

Believe it or not, my pilot is still stock (43? I think) and so is the air screw. I havent touched either.

I do get the occasional dreaded "bog" when you blip the throttle but I hate to mess with my carb settings anymore than I have to as long as its running good for me.
I'll just end up making matters worse.

p.s. I did drop the needle on the clip one position. to #3 (it helped a lot on cold starting)

MichaelAngelo

Mo...thanks again for the reply...I think I might go back to the 48 pilot, unless I go to the YZ 250 two smoke air box. I called the dealer and this is only an $80 part. I've hear that this mod really opens thins up.

SFO

MichaelAngelo

SFO...I am using the stock needle. I thought I read somewhere on this forum of people using the yz250 2-stroke airbox. It is similar to the carbon fiber one advertized for $499; I like the idea of eighty bucks a whole lot better. Anyone out there using this 2-stroke mod?

arrow101

do the air box mod it works awesomly, all you need is a air box from a 96-01 YZ 250 2-stroke, the 2-stroke side covers and the speed nuts and bolts to hold the sidecovers to the box. It slips in easy a little trimming is required near the top front stock WRF airbox mount.
I cant remember what exactly my bike has in it as it was neer on 4 years ago i set it up but it is a 98 WR and will eat an 01 WR 426 so it must be doing sonething right. And it still has the power to give me 2 dislocated shoulders and one broken shoulder when it gets angry!!!! i recomend doing the engin mod not the body damage

arrow101

do the air box mod it works awesomly, all you need is a air box from a 96-01 YZ 250 2-stroke, the 2-stroke side covers and the speed nuts and bolts to hold the sidecovers to the box. It slips in easy a little trimming is required near the top front stock WRF airbox mount.
I cant remember what exactly my bike has in it as it was neer on 4 years ago i set it up but it is a 98 WR and will eat an 01 WR 426 so it must be doing sonething right. And it still has the power to give me 2 dislocated shoulders and one broken shoulder when it gets angry!!!! i recomend doing the engin mod not the body damage

Rich_in_Orlando

My 99 WR came with a 180 main and DTM needle. I thought it was so great...until I started leaning the bike out. Do you ever notice the top end just kind of die away and you stop accelerating? Pump the throttle and then it will speed up on top? That's what mine was doing until I went to a 160 MJ, 35 PJ, 55 PAJ, 160 MAJ, 60 SJ and EMM needle. The leaner configuration didn't cost much ($20?) and this thing gets going like never before. I didn't believe it until I did it for myself. And I'm going a bit leaner as the weather warms up. I recently dropped to from a 160 MJ to the 158 because the temps are in the low 90's these days. I'm also planning to screw in my PAJ screw to get rid of a little low-mid throttle vibration. (I think Taffy recommended the 45 PAJ setting. How many turns out is that again?)

Bill

I have also been the route of the DTM, DVP, EKP and now the EMM and leaner overall settings. I'm sure once I get rid of my mid range richness, my jetting will once again be a step better, than the previous configuration.

Rich_in_Orlando

endurodog

Hey guys the Mikuni carbs run jets in these number ranges. They are shorter than than the ones we run in our WR's but they numbers are in the 300 and 400's. My 2001 YZ125 main jet stock is a 460, thats out of the manual.